JP2001004600A5

JP2001004600A5 -

Info

Publication number: JP2001004600A5
Application number: JP1999171151A
Authority: JP
Filing date: 1999-06-17
Publication date: 2005-06-16
Anticipated expiration: 2019-06-17

Description

【０００９】
【課題を解決するための手段】
前記課題を解決するための第１の手段は、表面波の超音波を用いて透過法により被検査体の表面傷を検出する方法であって、複数の周波数成分を含む超音波を使用し、被検査体を透過する超音波の透過量を周波数毎に求め、周波数毎に求めた被検査体の健全部を透過する超音波の透過量で正規化し、正規化された透過量の周波数分布のパターンから、表面傷の種類と深さを検出することを特徴とする表面傷の検出方法（請求項１）である。 0009
[Means for solving problems]
The first means for solving the above-mentioned problems is a method of detecting surface scratches on an object to be inspected by a transmission method using ultrasonic waves of surface waves, using ultrasonic waves containing a plurality of frequency components. The amount of ultrasonic waves transmitted through the subject to be inspected is determined for each frequency, and the amount of ultrasonic waves transmitted through the sound part of the subject to be inspected is normalized by the amount of ultrasonic waves transmitted through the sound part of the subject to be inspected. A method for detecting surface scratches (claim 1), which comprises detecting the type and depth of surface scratches from a pattern.

前述したような理由により、表面波である超音波の透過量は、表面傷以外の種々の要因の影響を受けるが、発明者等の実験によれば、超音波の透過率の周波数分布のパターンは、被検査体と測定条件が同一であれば、表面傷の種類と深さによって決まってしまい、前述したような外乱の影響を受けない。よって、複数の周波数成分を含む超音波を使用し、被検査体を透過する超音波の透過量を周波数毎に求め、周波数毎に求めた非検査体の健全部を透過する超音波の透過量で正規化し、正規化された透過量の周波数分布のパターンを測定することにより、外乱の影響を受けることなく、表面傷の種類と深さを検出することができる。また、本方法によれば、傷の方向にかかわりなく、表面傷の種類と深さを検出することができる。 For the reasons described above, the transmission amount of ultrasonic waves, which are surface waves, is affected by various factors other than surface scratches, but according to experiments by the inventors, the frequency distribution pattern of ultrasonic wave transmittance Is determined by the type and depth of surface scratches if the measurement conditions are the same as those of the object to be inspected, and is not affected by the above-mentioned disturbance. Therefore, using ultrasonic waves containing a plurality of frequency components, the amount of ultrasonic waves transmitted through the inspected object is determined for each frequency, and the amount of ultrasonic waves transmitted through the sound part of the non-inspected object obtained for each frequency is obtained. By measuring the frequency distribution pattern of the normalized transmission amount, it is possible to detect the type and depth of surface scratches without being affected by disturbance. Further, according to this method, the type and depth of surface scratches can be detected regardless of the direction of the scratches.

前記課題を解決するための第２の手段は、前記第１の手段であって、予め種々の表面傷に対して、深さを異ならせた場合の、透過量の周波数分布のパターンを測定し、周波数毎に求めた被検査体の健全部を透過する超音波の透過量で正規化して基準パターンとして記憶しておき、探傷時には、被検査体を透過する超音波の透過量を周波数毎に求め、周波数毎に求めた被検査体の健全部を透過する超音波の透過量で正規化し、正規化された透過量の周波数分布のパターンと、記憶された基準パターンとのパターンマッチングを行い、最も一致率の高い記憶された基準パターンに対応する表面傷の種類と深さを、検出値とすることを特徴とするもの（請求項２）である。 The second means for solving the above problem is the first means, in which the frequency distribution pattern of the transmission amount is measured in advance for various surface scratches at different depths. , Normalized by the amount of ultrasonic waves transmitted through the sound part of the inspected object obtained for each frequency and stored as a reference pattern, and at the time of flaw detection, the amount of ultrasonic waves transmitted through the inspected object is measured for each frequency. It was obtained, normalized by the amount of ultrasonic waves transmitted through the sound part of the subject to be inspected obtained for each frequency, and pattern matching was performed between the frequency distribution pattern of the normalized amount of transmission and the stored reference pattern. The detection value is the type and depth of surface scratches corresponding to the memorized reference pattern having the highest matching rate (claim 2).

前記課題を解決するための第３の手段は、表面波の超音波を用いて透過法により被検査体の表面傷を検出する方法であって、複数の周波数成分を含む超音波を使用し、被検査体を透過する超音波の透過量を周波数毎に求め、送信波の周波数分布で正規化した透過量、すなわち透過率を周波数毎に求め、求められた透過率の周波数分布のパターンから、表面傷の種類と深さを検出することを特徴とする表面傷の検出方法（請求項３）である。 A third means for solving the above-mentioned problems is a method of detecting surface scratches on an object to be inspected by a transmission method using ultrasonic waves of surface waves, using ultrasonic waves containing a plurality of frequency components. The amount of ultrasonic waves transmitted through the object to be inspected is obtained for each frequency, and the amount of transmission normalized by the frequency distribution of the transmitted wave, that is, the transmittance is obtained for each frequency, and from the frequency distribution pattern of the obtained transmittance, A method for detecting surface scratches (claim 3), which comprises detecting the type and depth of surface scratches.

前記課題を解決するための第５の手段は、前記第１の手段から第５の手段のいずれかであって、正規化された透過量の周波数分布のパターンにおいて、低周波側の正規化された透過量の減衰が高周波側の正規化された透過量の減衰に比して小さい場合に開口傷、低周波側の正規化された透過量の減衰が高周波側の正規化された透過量の減衰に比して大きい場合に非開口傷と判断することを特徴とするもの（請求項５）である。 The fifth means for solving the above-mentioned problems is any one of the first to fifth means, in which the frequency distribution pattern of the normalized transmission amount is normalized on the low frequency side. permeation amount of attenuation open wound is smaller than the attenuation of normalized permeation amount of the high frequency side attenuation of normalized permeation amount of the low-frequency side of normalized permeation amount of the high-frequency side It is characterized in that it is determined as a non-opening scratch when it is larger than the attenuation (claim 5).

前記課題を解決するための第６の手段は、被検査体の表面に存在する表面傷の種類と深さを、超音波の表面波を用いて透過法で検出する表面欠陥探傷装置であって、複数の周波数成分を含有する表面波の超音波を送信する送信器と、被検査体を透過した超音波を受信する受信器と、受信した超音波より周波数分布を求める手段と、求められた周波数分布を、被検査体の健全部を透過した送信波の周波数分布で除算して、正規化された超音波の透過量の周波数分布を求める除算器と、前記送信器より送信された超音波の、所定種類の表面傷に対する透過量の周波数分布を、被検査体の健全部を透過した透過波の周波数分布で除算して、正規化された透過量の周波数分布のパターンを、当該表面傷の深さ毎に基準パターンとして記憶する記憶装置と、探傷に際して求められた、正規化された超音波の透過量の周波数分布の形状に最も近い、記憶装置に記憶されている基準パターンを選定する演算装置と、選定された基準パターンより、表面傷の種類と深さを判定する判定装置とを有してなることを特徴とする表面欠陥探傷装置（請求項６）である。 The sixth means for solving the above-mentioned problems is a surface defect flaw detector that detects the type and depth of surface scratches existing on the surface of the object to be inspected by a transmission method using an ultrasonic surface wave. , A transmitter that transmits surface wave ultrasonic waves containing a plurality of frequency components, a receiver that receives ultrasonic waves transmitted through an inspected object, and a means for obtaining a frequency distribution from the received ultrasonic waves. A divider that divides the frequency distribution by the frequency distribution of the transmitted wave that has passed through the sound part of the inspected object to obtain the frequency distribution of the normalized amount of transmitted ultrasonic waves, and the ultrasonic waves transmitted from the transmitter. The frequency distribution of the transmitted amount for a predetermined type of surface scratch is divided by the frequency distribution of the transmitted wave transmitted through the sound part of the inspected object, and the normalized frequency distribution pattern of the transmitted amount is obtained from the surface scratch. Select a storage device that stores as a reference pattern for each depth, and a reference pattern that is stored in the storage device that is closest to the shape of the frequency distribution of the normalized ultrasonic transmission amount obtained during flaw detection. The surface defect flaw detection device (claim 6) is characterized by including a calculation device and a determination device for determining the type and depth of surface scratches based on a selected reference pattern.

また、この実施の形態においては、超音波の透過量を正規化する手段として、受信波のスペクトル分布を、被検査体の健全部を透過した透過波のスペクトル分布で割る方法を用いているが、被検査体の健全部を透過した透過波のスペクトル分布の代わりに、送信波のスペクトル分布で割ってもよい。この場合には、正規化された透過量として、超音波の透過率のスペクトル分布を使用することになる。この場合の検査の手順は、「正規化された透過量」という趣旨の記述を「透過率」に置換えることにより、前述の手順がそのまま適用できる。
Further, in this embodiment, as a means for normalizing the transmitted amount of ultrasonic waves, a method of dividing the spectral distribution of the received wave by the spectral distribution of the transmitted wave transmitted through the sound part of the inspected object is used. , Instead of the spectral distribution of the transmitted wave transmitted through the sound part of the inspected object, it may be divided by the spectral distribution of the transmitted wave. In this case, the spectral distribution of the ultrasonic transmittance is used as the normalized transmittance. As for the inspection procedure in this case, the above-mentioned procedure can be applied as it is by replacing the description of "normalized transmittance" with "transmittance".

Claims

A method of detecting surface flaws of an object to be inspected by a transmission method using ultrasonic waves of surface waves, using ultrasonic waves including a plurality of frequency components, and the amount of ultrasonic waves transmitted through the object to be inspected as a frequency. Obtained for each frequency, normalized by the amount of ultrasonic transmission that passes through the healthy part of the object to be inspected for each frequency, and detects the type and depth of surface flaws from the frequency distribution pattern of the normalized transmission amount A method for detecting surface flaws.

The surface flaw detection method according to claim 1, wherein a pattern of a frequency distribution of a transmission amount when a depth is varied in advance with respect to various surface flaws is measured, and a target obtained for each frequency is measured. Normalized by the amount of ultrasonic transmission that passes through the healthy part of the test object and stored as a reference pattern, and at the time of flaw detection, the amount of ultrasonic transmission that passes through the inspection target was determined for each frequency and determined for each frequency. Normalized with the amount of ultrasonic transmission that passes through the healthy part of the object to be inspected, and performs pattern matching between the normalized frequency distribution pattern of the transmitted amount and the stored reference pattern, and stores the highest matching rate. A method for detecting a surface flaw, wherein the detected value is the type and depth of the surface flaw corresponding to the reference pattern.

A method of detecting surface flaws of an object to be inspected by a transmission method using ultrasonic waves of surface waves, using ultrasonic waves including a plurality of frequency components, and the amount of ultrasonic waves transmitted through the object to be inspected as a frequency. The amount of transmission flaws obtained by normalization with the frequency distribution of transmitted waves, that is, the transmittance is obtained for each frequency, and the type and depth of surface flaws are detected from the frequency distribution pattern of the obtained transmittance. A method for detecting surface scratches.

The method for detecting a surface flaw according to claim 3, wherein a pattern of a frequency distribution of transmittance is measured and stored as a reference pattern when depths are varied in advance for various surface flaws. The pattern of the frequency distribution of transmittance detected at the time of flaw detection is matched with the stored reference pattern, and the type and depth of the surface flaw corresponding to the reference pattern with the highest match rate are detected and A method for detecting a surface flaw characterized by comprising:

The detection process of surface flaws as set forth in claim 1 any one of claims 4, in the pattern of the frequency distribution of normalized permeation amount, normalized permeation amount of the low frequency side attenuation than but open wound is smaller than the attenuation of normalized permeation amount of the high-frequency side, the attenuation of normalized permeation amount of the low-frequency side of normalized permeation amount of the high frequency side attenuation A method for detecting a surface flaw, characterized in that it is determined as a non-opening flaw when it is large.

A surface defect flaw detector that detects the type and depth of surface flaws existing on the surface of an object to be inspected by a transmission method using ultrasonic surface waves, and ultrasonic waves of surface waves containing multiple frequency components A transmitter for transmitting the ultrasonic wave, a receiver for receiving the ultrasonic wave transmitted through the object to be inspected, a means for obtaining the frequency distribution from the received ultrasonic wave, and the obtained frequency distribution transmitted through the healthy part of the object to be inspected A divider for dividing the frequency distribution of the transmission wave to obtain a normalized ultrasonic transmission amount frequency distribution, and a transmission frequency distribution of the ultrasonic wave transmitted from the transmitter with respect to a predetermined type of surface flaw Is divided by the frequency distribution of the transmitted wave that has passed through the healthy part of the object to be inspected, and a storage device that stores the normalized frequency distribution pattern of the transmission amount as a reference pattern for each depth of the surface scratches; Sought for flaw detection, normalized An arithmetic device that selects a reference pattern stored in a storage device that is closest to the shape of the frequency distribution of the amount of transmitted ultrasonic waves, and a determination device that determines the type and depth of surface flaws from the selected reference pattern A surface defect inspection device characterized by comprising:

A surface defect flaw detector that detects the type and depth of surface flaws existing on the surface of an object to be inspected using a transmission method using ultrasonic surface waves, and ultrasonic waves of surface waves containing multiple frequency components A transmitter for transmitting the ultrasonic wave, a receiver for receiving the ultrasonic wave transmitted through the object to be inspected, means for obtaining a frequency distribution from the received ultrasonic wave, and dividing the obtained frequency distribution by the frequency distribution of the transmitted wave A divider for obtaining the frequency distribution of the transmittance of the sound wave, and the shape of the frequency distribution of the transmittance for the predetermined type of surface flaw of the ultrasonic wave transmitted from the transmitter as a reference pattern for each depth of the surface flaw A storage device for storing, an arithmetic device for selecting a reference pattern stored in the storage device that is closest to the shape of the frequency distribution of the transmittance of ultrasonic waves obtained at the time of flaw detection, and a surface scratch from the selected reference pattern Type and depth Determining device and the surface defect inspection apparatus characterized by comprising a.